Add to List from codebehind C# Asp.net

Question

I have a UL list in a ASPX page:

<ul id="tabs">
 <li id="tab1"><a href="ztab1.htm">Tab 1</a></li>
 <li id="tab2"><a href="ztab2.htm">Tab 2</a></li>
 <li id="tab3"><a href="ztab3.htm">Tab 3</a></li>
 <li id="tab4"><a href="ztab4.htm">Tab 4</a></li>
 </ul> 

I would like to add list items dynamically from codebehind, including the href entry for each new list item.

How?

Answer 1

You need to mark your ul as a server side control, then treat the 'new item' as a HtmlGenericControl and insert it into the control collection:

<ul runat="server" id="tabs"> 

To add the item, create a new element and add it:

HtmlGenericControl li = new HtmlGenericControl("li");
tabs.Controls.Add(li);

HtmlGenericControl anchor = new HtmlGenericControl("a");
anchor.Attributes.Add("href", "page.htm");
anchor.InnerText = "TabX";

li.Controls.Add(anchor);

Answer 2

Use asp:bulletedList and your list will be much easier.

<asp:BulletedList id="blTabs" 
  BulletStyle="Disc"
  DisplayMode="LinkButton" 
  runat="server">
    <asp:ListItem Value="ztab1.htm">tab1</asp:ListItem>
    <asp:ListItem Value="ztab2.htm">tab2</asp:ListItem>
    <asp:ListItem Value="ztab3.htm">tab3</asp:ListItem>
</asp:BulletedList>

Code Behind:

    ListItem li = new ListItem();
    li.Value = "*.html";  //html goes here i.e.  xtab1.html
    li.Text = "New Text";  //text name goes i.e. here tab1
    blTabs.Items.Add(li);

Answer 3

This result is the same as GenericTypeTea's, but the difference is the HTML is 'written' in the code behind and injected into the page.

In your markup:

<asp:Literal id="litMarkup" runat="server" />

In your code behind:

List<string> locations  // however this initialized 

StringBuilder sb = new StringBuilder();

sb.Append("<ul id=\"tabs\">");

for (int i = 0; i < locations.Count; i++)
{
   sb.Append("<li id=\"tab" + i.ToString() + "\"><a href=\"" + locations[i] + "\">Tab " + i.ToString() + "</a></li>");
}

sb.Append("</ul>");

litMarkup.Text = sb.ToString();

Answer 4

You can create a dynamic UL by using an asp:Repeater Control

You can use repeater in following way, in your .aspx file

<asp:Repeater ID="menu_ul_1" runat="server">
    <HeaderTemplate>
    <ul class="my-menu">
    </HeaderTemplate>
    <ItemTemplate>
        <li>
        <a href='<%# Eval("href_li")%>'>
        <%# Eval("DisplayText")%></a>
        </li>
    </ItemTemplate>
    <FooterTemplate>
        </ul>
    </FooterTemplate>
</asp:Repeater>

And you can put dynamic data via code behind in .aspx.cs file

protected void Page_Load(object sender, EventArgs e)
{
    DataTable newsDataTable = new DataTable();

    // add some columns to our datatable
    newsDataTable.Columns.Add("href_li");
    newsDataTable.Columns.Add("DisplayText");

    for (int i = 1; i <= 5; i++)
    {
        DataRow newsDataRow = newsDataTable.NewRow();
        newsDataRow["href_li"] = "?sc=item_" + i;
        newsDataRow["DisplayText"] = "List Item # "+i;
        newsDataTable.Rows.Add(newsDataRow);
    }
    menu_ul_1.DataSource = newsDataTable;
    menu_ul_1.DataBind();
}

Result: You will get following html through this code

<ul class="my-menu">
    <li><a href='?sc=item_1'>List Item # 1</a> </li>
    <li><a href='?sc=item_2'>List Item # 2</a> </li>
    <li><a href='?sc=item_3'>List Item # 3</a> </li>
    <li><a href='?sc=item_4'>List Item # 4</a> </li>
    <li><a href='?sc=item_5'>List Item # 5</a> </li>
</ul>